Microchemical identification of gamma-hydroxybutyrate (GHB)

A new microcrystal test for the detection of gamma-hydroxybutyrate (GHB) is described. The silver/copper reagent consists of an aqueous solution of 0.1 g of cupric nitrate and 0.1 g of silver nitrate in 10.0 mL water. While some crystals form upon evaporation of the reagent, the test forms distinctive crystals for GHB and does not form crystals with some commonly encountered controlled substances. The reagent was also tested against some controlled substances that have similar biological activity to GHB, including flunitrazepam, and some barbiturates. No crystals were observed with these compounds. A blind test was performed to determine if GHB could be discriminated from the other compounds. Two of ten unknowns were correctly identified as GHB--one solid, one liquid. One GHB sample was not identified as GHB and the remaining seven non-GHB samples were not identified as GHB. The reagent is therefore selective for GHB, but not extremely sensitive.